The flexible laminae of such lamina valves previously have been almost exclusively clamped by wedging in the plane of a gasket which is inserted between the seating plate and its adjacent member which follows this. Generally however, the laminae are thinner than the gasket, so that it is not possible to easily clamp them together with the gasket. A number of special measures must be taken to obtain film clamping. Furthermore, it is important in lamina valves for the laminae not to slip during assembly and to be clamped in the correct position, as otherwise they are unable to tightly cover the ports in the seating plate.
It is known to compensate for the difference in thickness between the laminae and gasket by means of a spacer of resilient material, which is inserted under the clamped region of the lamina before the clamping operation. The position of the lamina is ensured in this case by two pins which are anchored relative to the seating plate and pass through bores in the lamina and spacer. German Offenlegungsschrift No. 2,260,520 describes such a construction in which a wedge of metal is used as the spacer, which can be fixed to the side of the lamina. According to German Auslegeschrift No. 1,129,784, a depression is provided for the clamped region of the lamina in that clamping surface facing the seating plate, and the gasket is placed first over this depression. This therefore dispenses with a separate spacer, but it is necessary to provide the depression and this represents an additional cost.